Latching assembly with magnetic locking

ABSTRACT

A latching assembly for a door swingable toward and away from a doorjamb or the like between a closed and an open position, comprising a pair of mechanically cooperating latch members mounted on the door and jamb, respectively, and relatively movable between an engaged latching position and a disengaged unlatched position. The latch members have latching surfaces adapted for engaged contact in a first direction generally transversely of the direction of movement of an adjacent portion of said door relative to the doorjamb. Permanent magnet holding means is provided for normally locking said latch members in latched contact, and electromagnetic means is provided for producing a magnetic force with a polarity opposing that of said permanent magnet means to unlock and relatively move the latch members out of latched engagement thereby permitting the door to be opened.

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[54] LATCHHNG ASSEMBLY Wll'lll-ii MAGNETM: LQCKING Primary Examiner-Robert Wolfe Att0rneyMason, Kolehmainen, Rath'bum & Wyss [72] Inventor: Henry A. Waller, Los Angeles, Calif.

[73] Assignee: Consolidated Controls Corporation, [57] ABSTRACT Bethel, Conn- A latchin assembly for a door swingable toward and awa g Y [22] Filed. 5 1969 from a doorjamb or the like between a closed and an open position, comprising a pair of mechanically cooperating latch [211 App]. No.: 874,134 members mounted on the door and jamb, respectively, and relatively movable between an engaged latching position and a disengaged unlatched position. The latch members have latching surfaces adapted for engaged contact in a first 58] i 5 20] 34 l 6 direction generally transversely of the direction of movement "292/276' of an adjacent portion of said door relative to the doorjamb. Permanent magnet holding means is provided for normally [56] References Cited locking said latch members in latched contact, and electromagnetic means is provided for producing a magnetic force UNITED STATES PATENTS with a polarity opposing that of said permanent magnet means to unlock and relatively move the latch members out of 3 latched engagement thereby permitting the door to be e 3 ar openmi 2,888,290 5/1959 Pierce... ...292/251.5 3,312,492 4/1967 Remhof ..292/20l 13 Claims, 5 Drawing ll igures LATCIIINGASSEMBLY WITH MAGNETIC LOCKING The present invention relates to a magnetic latching assembly, and more particularly to a latching assembly wherein magnetic forces are used to hold a pair of latch members in mechanically locked engagement.

The magnetic latching assembly of the present invention is particularly well suited for application in modern aircraft for latching doors or closure panels for compartments containing oxygen equipment and masks for the passengers. In this specific application it is desirable that the latching assembly be hidden or generally unaccessible to the passenger and preferably mounted on the inside of the door or closure member within the compartment which contains the oxygen mask. Means must be provided, however, whereby a passenger, with proper instruction, can manually unlatch the latch assembly from the outside so that in cases of emergency, when the normal electrical unlatching system fails, the door can be opened and access can be had to the oxygen equipment inside the compartment.

The latching assembly of the invention is arranged so that the latching or holding means which maintains the door in a closed or shut position is not dependent on magnetic force but instead is provided by a positive mechanical latching engagement between surfaces of cooperating latch members and thus the assembly is able to withstand considerable G loading, such as might be caused by rapid aircraft acceleration or by hammering on the door with an arm, or fist, or a piece of luggage. The latching assembly of the present invention is normally unlatched by a controlled electrical impulse delivered at the desired time, and the energy of the impulse may also aid in opening the door.

The previously described features are objects of the present invention, and it is an object of the invention to provide a new and improved door latch assembly in which permanent magnet means is used for normally holding or locking a pair of latch members in a positive mechanical latched engagement. Unlocking is accomplished by electromagnetic means in opposition to said permanent magnet means, and unlatching is normally accomplished electrically.

Another object of the present invention is to provide a new and improved door latching assembly of the character described wherein an electromagnetic force is provided to overcome the holding or looking force of a permanent magnet means and is additionally effective to aid in opening the door with which the latching assembly is associated.

Another object of the present invention is to provide a new and improved latching assembly which may be hidden in a compartment on the inside of an access door thereof, yet which may be latched or unlatched from outside of the compartment by means of a tool or finger inserted through a window or opening in the door or compartment wall manipulated exteriorly thereof.

Another object of the invention is to provide a new and improved latching assembly of the character described including means for indicating when the assembly is in an unlatched position.

Another object of the invention is to provide a new and improved magnetic latching assembly wherein the latching or holding force is provided by mechanically engaged latching surfaces extending generally transverse to the direction of movement of the door relative to the doorjamb, and the locking force for maintaining latch engagement is provided by permanent magnet means acting in a similar direction.

Briefly, the foregoing and other important objects and advantages of the present invention are accomplished in an illustrated embodiment comprising a new and improved latching assembly having a pair of latch members mounted on a door and doorjamb, respectively, and movable relatively between an engaged, latched position and disengaged, unlatched position. Permanent magnet holding or locking means is provided for normally maintaining thelatch members in an engaged latched condition, and electromagnet means is provided for momentarily opposing and nullifying the magnetic holding force with a force of opposing polarity for moving the latch members to an unlatched position, permitting the door to be opened.

For a better understanding of the present invention, reference should be had to the following detailed description, taken in conjunction with the claims and drawings, in which:

FIG. I is a side elevation view of a typical aircraft seat including a compartment in the back thereof containing emergency oxygen equipment for the passengers on the aircraft;

FIG. 2 is an enlarged sectional view taken on a vertical plane through the aircraft seat of FIG. 11 showing the compartment and closure door thereof in enlarged detail with a door latching assembly constructed in accordance with the features of the present invention;

FIG. 3 is a sectional view showing the latching assembly as seen in the direction of arrows 3-3;

FIG. 4 is an enlarged sectional view similar to FIG. 2 showing another embodiment of the latching assembly constructed in accordance with the features of the present invention; and

FIG. 5 is an elevational view of the latching assembly of FIG. 4 as seen in the direction of arrows 5-5.

Referring now more particularly to the drawings, in FIG. 1 is illustrated a typical aircraft seat 10 having a base 12 permanently attached to the floor 14 of an aircraft or other vehicle and an upstanding back portion 16 with an upper head rest 16a. The upstanding back portion 16 is pivotally mounted on the seat base 12 for angular adjustment to provide for comfort of the passengers in the aircraft. In order to provide oxygen for the passengers in case of an emergency, an enclosure or compartment 26 is mounted in the back portion 16 of each seat 10, and the compartment is adapted to contain an oxygen mask and possibly other emergency equipment needed. The

compartment 26 includes a pair of vertical sidewalls 11, a bottom wall 13, a rear or backwall 15, and a top wall 17, the forward edge portion 24 of which forms a jamb for a door 30. The door 30 is normally closed so that the interior of the compartment 26 is not accessible to the passengers except in an emergency. The door is hinged to the bottom wall 13 of the compartment and is pivotable from a closed position (FIGS. 2 and 4) to an open position (dotted lines FIG. 1).

In accordance with the features of the present invention, a new and improved latching mechanism 20 comprises a first latching subassembly 22 mounted on the inside surface of the compartment doorjamb 24 and a second subassembly 28 mounted adjacent the upper edge on the inside surface of the compartment door 30. The latching subassembly 22 includes a bracket 32 preferably stamped from thin steel sheet or other sheet material which is capable of being magnetized but which does not retain permanent magnetismto any great extent. The bracket 32 includes a base 34 having a pair of parallel elongated slots 36 formed therein for receiving sheet metal screws 38 or other appropriate fasteners for securing the subassembly in place on the compartment wall 17. The bracket includes a pair of upstanding, spaced apart, parallel flanges 40 at opposite ends of the base 34, and each flange is formed with a circular opening therein to receive and support one end of an elongated, cylindrical, soft iron core 42 which is intermittently magnetized by an annular coil 44 energized by the leads 44a (FIG. 2).

At opposite ends of the coil adjacent the support bracket flanges 40 there is provided a pair of pole pieces 46 each having a circular opening therein to accommodate the cylindrical core 42 of the electromagnetic coil assembly. The pole pieces 46 extend radially outwardly of the axis of the coil and are temporarily magnetized when the coil. is energized. At the outer ends of each pole piece is provided a latching finger or lug 46a having a latching surface aligned on a plane (represented by the dotted line B-B), which is generally perpendicular or normal to the arrow A" (FIG. 2) representing the general direction of door opening movement at the upper end of the compartment. The latching surfaces on the lugs 46a cooperate to provide positive, mechanical, latched engagcment with an elongated latch bar 48 of permanently magnetic material. The latch bar 48 is pivotally mounted on the compartment access door 30 and is movable into and out of latching .engagement with the lugs 46a on the as indicated by the arrow C in FIG. 2.

As shown in FIG. 3, the permanent magnet latching bar has north andsouth poles at opposite ends designated by the letters N and S, and when the coil 44 is not energized the magnetic bar 48 and the readily magnetizable' pole pieces 46 are attracted together with sufficient magnetic force to maintain latching engagement between one comer edge of the bar and the latching surfaces on the lugs 46a, as shown in FIG. 2. It should be noted that the magnetic attractive forces between the pole pieces 46 and the permanent magnetic latch bar 48 are used only for holding or locking the latch assemblies in latched engagement, and that positive mechanical latching by engaged surfaces along the plate B--B is provided to mechanically hold the door 30 in the closed position. Accordingly, the latching assembly 20 is able to withstand much higher forces tending to open the door 30 than would be possible if magnetic attraction alone were the only force holding the door closed.

The electrical leads 44a of the coil 44 are preferably color coded to insure proper polarity so that when current is supplied to the coil, the pole pieces 46 are magnetized with a polarity to establish repelling forces in direct opposition against the poles of the permanent magnet 48. In FIG. 3, the poles are labeled 46n and 46s, respectively, indicating their polarity when the coil 44 is energized, and in this condition the poles repel and the permanent magnet latching bar 48 is repelled outwardly out of latching engagement in the direction of the arrow C to the unlatched position shown in dotted lines in FIG. 1.

From the foregoing, it will be seen that the latch assembly 20 is maintained or held in the latched position as shown in solid lines in FIG. 2 by an attractive magnetic holding force between the permanent magnet latch bar 48 and the pole pieces 46, but the door 30 is latched in the closed position by positive mechanical latching engagement between engaging latching surfaces on the bar 48 and lugs 46a generally normal or perpendicular to the direction of swinging movement (arrow A) of the door 30 away from the jamb 24. When the coil 44 is energized, the core 42 and pole pieces 46n and 46s become magnetized. Repelling magnetic forces are developed pole pieces 46,

' between adjacent like poles of the latch bar 48 and the pole pieces 46 causing the latch bar to be pivoted out of latching engagement (arrow "C clockwise in FIG. 2) to the unlatched position shown as dotted lines. Upon disengagement between the magnet bar 48 and pole piece lugs 4611, the door 30 is free to be opened.

The latching assembly 20 is extremely well suited for use with oxygen compartment doors on the back of aircraft seats. In this location the doors 30 are subject to frequent bumping, prying, and jamming forces from the passengers in addition to the normal acceleration, deceleration, centrifugal and gravity forces encountered because of aircraft flight. Because of these relatively high forces, a positive mechanically engageable latching system is required rather than a system wherein the only force available for holding the door shut is a magnetic force.

The latching subassembly 28 includes a bracket 50 having a base 52 adapted to be affixed or secured to the inside surface of the door 30 by a pair of screws 54 or other suitable fasteners. The bracket 50 includes a pair of spaced apart upstanding flanges 56 for supporting a pin 58 extending through aligned openings therein and the pin pivotally supports a latch I arm or lever 60 on-which the permanent magnet latch bar 48 is mounted adjacent the outer end. The latch lever 60 is formed with a pocket adjacent the outer'end to receive the magnet bar 48 which extends perpendicular or transverse thereto. The lever 60 is supported on a pin 58 forpivotal movement and is biased in a clockwise direction (arrow C FIG. 2) from the latched or engaged position (solid lines) toward the unlatched or disengaged position (dotted lines) by a spring member 62 having several loops or coils disposed on the pin 58 on opposite sides of the lever.

' lever remains in the unlatched position until relatched, as will be described hereinafter. In this connection, it should be noted that the enga'geable latching surfaces of the lugs 46a and bar 48 are positioned in a plane (B-B, FIG; 2) which is generally perpendicular to a radius extending through the pivot axis of the pin 58.

In accordance with the present invention, the door 30 is formed with a slot, window or opening 30.: in front of the lever 60, and a curved indicator finger 64 is attached to the lever and is adapted to project outwardly through the window 30a (dotted lines, FIG. 2) or is visible through the window whenever the latching assembly 20 is in an unlatched position. The finger 64 visually indicates that the latching assembly is unlatched even though the door 30 remains closed. The finger 64 also serves as a means for moving the latch bar magnetic 48 into latched engagement with the lugs 46a of the pole pieces. To this end a rod, pencil, screwdriver, or other implement can be inserted through the window 30a in the door-30 while the door is closed. The inserted end of the rod is engaged against the outer end of the indicating finger 64 and is moved to pivot the lever 60 in a counterclockwise direction against the force of the spring 62 until latching engagement is established between the latch bar 48 and the pole piece lugs 46a. Once latching engagement is established, the magnetic attraction between the latch bar 48 and pole pieces 46 is sufficient to overcome the bias of the spring 62 and maintain latched engagement.

If it is desired to unlatch the system manually because of a failure in the electrical system for energizing the coil 44, a pencil, pen, or other implement can be inserted through an opening 30b (FIG. 2) in the door and thrust against a finger 66 connected to the latch lever 60 and extending in a generally opposite direction and angularly disposed from the indicator finger 64. Engagement of the implement against the finger 66 causes the lever 60 to pivot in a clockwise direction and disengages the latch bar 48 from the lugs 46a until the magnetic attraction therebetween can no longer overcome the bias of the spring 62. The latching assembly 20 is normally unlatched electrically by energizing the coil 44 through the polarized leads 44a, but may also be manually unlatched by inserting a pencil, rod, etc., or other small implement through the opening 30b to engage the finger 66 as described. When the holding or locking force between the bar magnet 48 and pole pieces 46 is not of sufficient strength to overcome the bias of the spring. 62, the latch lever 60 then pivots in a clockwise direction to the unlatched position, and in'the unlatched position the indicating finger 64 can be seen through the opening 30a in the door, indicating that an unlatched condition exists.

The pivotally movable portion of the latching subassembly I 'gaged. In other words the components of the latching subassembly 28 which are supported for pivotal movement about the axis of the pin 58 are dynamically balanced so that the center of gravity of these components ison the pivot axis of the pin. Thus, all inertial forces causes by acceleration or deceleration in a vertical or horizontal direction of force component act through the axis of the pin 58 and have no ten dency to pivot the latch mechanism out of the latched position.

Referring to FIGS. 4 and 5, therein is illustrated another embodiment of a new and improved latching assembly constructed in accordance with the features of the present invention and referred to generally by the reference numerall20. Parts, components, and assemblies of the latching assembly 1120, which are similar or identical in structure or function to parts or components in the previously described latching assembly 20, are given the same reference numerals with the addition of a prefix l." Because of the basic similarity of the two embodiments, only the differences in structure or function will be described herein in detail.

The latching subassembly 112s of the latching mechanism 120 employs a pair of permanent bar magnets Mb (rather than a single bar magnet 48) for establishing mechanical latching engagement with the latch projections or lugs Mina on a pair of pole pieces M6 at opposite ends of a coil 1M and soft iron core M2.

As best shown in H6. 5, a pair of permanent magnet latching bars ll lll are mounted to extend laterally outwardly in opposite directions from the outer end portion of a latching lever 161]) which is pivotally mounted on a bracket supported pin 15%. The pair of permanent magnet latch bars Mid are arranged magnetically in series with one another (FIG. 5) to achieve a polarity in opposition to the polarity of the pole pieces Mb as established when the coil 14% is energized. The electromagnetized pole pieces Mb repel the magnets 1148 on the latch lever Ml] in the direction of the arrow C (clockwise, FIG. 45) out of a latched engaged position into an unlatched or disengaged position as shown in dotted lines. When in an unlatched position, an indicating finger 3164 is extended through or visually observable through an opening 130a in the door Ell, thus indicating that the mechanism is unlatched.

A coil spring M2 is effective to bias the latch lever 160) to pivot in a clockwise direction (arrow C) once the attractive holding or locking force between the magnets M8 and the pole pieces Mti is overcome.

Manual unlatching is accomplished by inserting a pencil or other implement through a small door opening 1130b to engage an end surface llfilla of the latch lever and thereby pivot the latch lever a sufficient amount to reduce the magnetic holding force or attraction between the pole pieces M6 and bar magnets l td so that the spring 1162 can take over. Latching is accomplished by engaging the outer end of the indicating finger 164i with a pencil, rod, tool or other implement and pivoting the latch lever w ll with the tip of the implement until latching engagement between the pole piece lugs 1146a and bar magnets ]Mlb is obtained. Magnetic attraction between the pole pieces Mn and the permanent bar magnets M8 provide sufiicient force to maintain a latched condition until the latching assembly is manually or electrically unlatched.

During a normal operating sequence, current is supplied to the coil l il l causing repelling magnetic forces to develop between the like poles of the adjacent pairs of pieces 1% and latch bar magnets Mb. These repelling magnetic forces cause the latch lever list) to pivot out of latched engagement in a clockwise direction as shown by the arrow C. As in the prior embodiment, a series magnetic circuit between the permanent magnet latch members ME and their supporting latch lever 160, and the pole pieces M6 and core M2, provide an ample holding or locking force for maintaining latched engagement between the latching subassemblies i122 and 12%, even though the spring 1162 acts in opposition.

As in the prior embodiment, the pivotally mounted components of the latching subassembly 12% are balanced about the axis of the pivot pin 15% so that the sum of the moments of the components is zero.

While several embodiments of the present invention have been here specifically disclosed, it will be apparent that many other variations may be made therein, all within the scope and spirit of the invention.

What is claimed and desired to be secured by Letters Patent of the United States is:

l. A latching assembly for adoor swingable toward and away from a doorjamb, said latching assembly comprising a pair of mechanically engageable latch members mounted on said door and jamb, respectively, and movable relatively,

engaged unlatched position, permanent magnet means for holding at least one of said latch members in mechanically latched engagement with the other, and electromagnet means having a polarity while energized opposing said permanent magnet means for overcoming the holding force thereof permitting relative movement of said latch members to said unlatched position so that said door can be opened.

2. The latch assembly of claim 1 wherein said latch members include engaging latch surfaces extending generally normal to the direction of movement of said door toward and toward and away from said doorjamb.

33. The latch assembly of claim ll wherein said holding force exerted by said permanent magnet means extends in a direction generally normal to the direction of movement of said door toward and away from said doorjamb.

l. The latch assembly of claim ll wherein one of said latch members is mounted for pivotal movement relative to the other and including spring means for biasing said pivotally mounted latch member out of said latching position to said unlatched position while the holding force of said permanent magnet means is overcome by said electromagnet means.

5. The latch assembly of claim 4 wherein said pivotally mounted latch member is supported on said door.

6. The latch assembly of claim 4 wherein said pivotally mounted latch member is balanced so that the sum of moments about its pivot axis equals zero.

7. The latch assembly of claim 1 in combination with a door having window means therein, said latch assembly including indicator means movable to a position viewable through said window means from outside said door when said latch mem bers are in said unlatched position and hidden from view when said latch members are engaged in said latched position.

b. The latch assembly of claim '7 wherein said indicator means is mounted on one of said latching members and said one latching member is mounted for pivotal movement relative to the other.

9. The latch assembly of claim 4 in combination with a door having window means therein, said pivotally mounted latch member including arm means extended outwardly of the pivot axis for engagement by a tool inserted through said window to pivotally move said latch members to said latched position engaging the other latch member.

lib. A latching assembly for a door swingable toward and away from a doorjamb, said latching assembly comprising a pair of latch members mounted on said door and jamb, respectively, and relatively movable between a mechanically engaged, latching position and a disengaged unlatched position, said latch members having latching surfaces engageable in a first direction generally transversely of the direction of movement of said door toward and away from said doorjamb, permanent magnet means and magnetic pole means normally magnetically attracted together for holding said latch members in said engaged latching position, and electromagnetic means for magnetizing said pole means with a polarity opposing that of said permanent magnet means to repel the same and thereby relatively move one of said latch members into said disengaged unlatched position permitting said door to be opened.

1111. The latching assembly of claim ll ll wherein one of said latch members is mounted for pivotal movement relative to the other between said latched and said unlatched position while said door is closed, and biasing means normally urging said pivotally mounted latch member toward said unlatched position in opposition to the holding force exerted by said per manent magnet means.

12. The latching assembly of claim llll wherein the force er- I erted by said electromagnet means while energized is active to pivot said pivotally mounted latch member in the same direction said member is urged by said bias means.

13. The latch assembly of claim wherein holding attraction between said permanent magnet means and said pole means is in a direction generally normal to the direction of movement of said door away from said doorjamb. 

1. A latching assembly for a door swingable toward and away from a doorjamb, said latching assembly comprising a pair of mechanically engageable latch members mounted on said door and jamb, respectively, and movable relatively between an engaged mechanically latched position and a disengaged unlatched position, permanent magnet means for holding at least one of said latch members in mechanically latched engagement with the other, and electromagnet means having a polarity while energized opposing said permanent magnet means for overcoming the holding force thereof permitting relative movement of said latch members to said unlatched position so that said door can be opened.
 2. The latch assembly of claim 1 wherein said latch members include engaging latch surfaces extending generally normal to the direction of movement of said door toward and toward and away from said doorjamb.
 3. The latch assembly of claim 1 wherein said holding force exerted by said permanent magnet means extends in a direction generally normal to the direction of movement of said door toward and away from said doorjamb.
 4. The latch assembly of claim 1 wherein one of said latch members is mounted for pivotal movement relative to the other and including spring means for biasing said pivotally mounted latch member out of said latching position to said unlatched position while the holding force of said permanent magnet means is overcome by said electromagnet means.
 5. The latch assembly of claim 4 wherein said pivotally mOunted latch member is supported on said door.
 6. The latch assembly of claim 4 wherein said pivotally mounted latch member is balanced so that the sum of moments about its pivot axis equals zero.
 7. The latch assembly of claim 1 in combination with a door having window means therein, said latch assembly including indicator means movable to a position viewable through said window means from outside said door when said latch members are in said unlatched position and hidden from view when said latch members are engaged in said latched position.
 8. The latch assembly of claim 7 wherein said indicator means is mounted on one of said latching members and said one latching member is mounted for pivotal movement relative to the other.
 9. The latch assembly of claim 4 in combination with a door having window means therein, said pivotally mounted latch member including arm means extended outwardly of the pivot axis for engagement by a tool inserted through said window to pivotally move said latch members to said latched position engaging the other latch member.
 10. A latching assembly for a door swingable toward and away from a doorjamb, said latching assembly comprising a pair of latch members mounted on said door and jamb, respectively, and relatively movable between a mechanically engaged, latching position and a disengaged unlatched position, said latch members having latching surfaces engageable in a first direction generally transversely of the direction of movement of said door toward and away from said doorjamb, permanent magnet means and magnetic pole means normally magnetically attracted together for holding said latch members in said engaged latching position, and electromagnetic means for magnetizing said pole means with a polarity opposing that of said permanent magnet means to repel the same and thereby relatively move one of said latch members into said disengaged unlatched position permitting said door to be opened.
 11. The latching assembly of claim 10 wherein one of said latch members is mounted for pivotal movement relative to the other between said latched and said unlatched position while said door is closed, and biasing means normally urging said pivotally mounted latch member toward said unlatched position in opposition to the holding force exerted by said permanent magnet means.
 12. The latching assembly of claim 11 wherein the force exerted by said electromagnet means while energized is active to pivot said pivotally mounted latch member in the same direction said member is urged by said bias means.
 13. The latch assembly of claim 10 wherein holding attraction between said permanent magnet means and said pole means is in a direction generally normal to the direction of movement of said door away from said doorjamb. 